Anglais : Exercice sur les pronoms relatifs

Read the following paragraph about renewable energy and complete the sentences using the correct relative pronouns (who, which, whose, where) or linking words.

'Solar energy, $1$. is considered a breakthrough in sustainable development, helps reduce the carbon footprint $2$. is a major goal for many countries. Scientists $3$. work in this field suggest that efficiency will increase by $15\%$ in the next decade, a change $4$. could revolutionize how we power our homes. This technology is particularly effective in regions $5$. the sun shines for more than $2500$ hours per year.'